Infants' visual short-term memory (VSTM) is typically assessed using the simultaneous streams change detection task (Ross-Sheehy et al., 2003). In this task, infants are presented with two stimulus streams, side-by-side, in which one or more colored squares appear briefly (for 500 ms), disappear briefly (for 300 ms), and then reappear briefly (for 500 ms); this cycle repeats continuously for the duration of the trials. One of the two streams is a changing stream, in which one randomly chosen item changes color on each cycle, and the other is a non-changing stream, in which the objects remain unchanged from cycle to cycle. VSTM ability is inferred from infants' preference for the changing stream. Exhibiting such a preference requires that infants perceive the two streams as separate and attend to the changing stream while inhibiting attention to the (distracting) non-changing stream. The eccentricity of the display may contribute to both processes, and therefore may have an impact on infants' ability to detect and prefer the changing stream. We examined the effect of eccentricity on 64 6-month-old infants' change detection at set sizes 1 and 2. The center-to-center distance of the two streams was either 44° or 27°. We found that infants exhibited a significant change preference only for the combination of set size 1 and 44° of eccentricity. No significant change preference was observed at set size 2 for either eccentricity, and no significant change preference was observed for either set size at 27° eccentricity. Thus, 6-month-old infants' ability to exhibit a preference for changing streams can be disrupted by decreasing the distance between stimulus streams. As smaller eccentricities, infants may perceive the two arrays together, or have difficulty inhibiting attention to the non-changing stream.